ACTIVE AND PASSIVE FILTER DESIGN PROGRAMS

 

These are BASIC programs, designed to run in GWBASIC which was shipped with most versions of DOS.  They should run in most versions of BASIC.  You will also need tables of low pass prototypes.  These are tables of component values for filters that have one ohm terminating resistance and one radian/sec cutoff frequency.  See filters.doc for more info.

You can download the programs and documentation by clicking on the name below and then on FILE and SAVE AS.  Save them in a folder on your hard drive.

All except the last two in this list are passive LC filters which need input from tables.  The last two are active RC filters which compute the component values in the program.

File Name Description
FILTMENU.TXT A BASIC program that provides a menu to the design programs
FILTERS.DOC Info on running these programs
LOPASS.TXT Does the transformations for frequency and source/load resistance for all pole designs.
HIPASXFM.TXT Transforms the low pass prototype to a high pass filter, all pole designs only.
BANDSTOP.TXT Transforms the low pass prototype to a band stop filter, all pole designs only.
LCBP.TXT Transforms the low pass prototype to a band pass filter, all pole designs only.
CCBPDES3.TXT Transforms the low pass prototype to a top coupled band pass filter, which is OK for narrow band filters, not good for wide band.
ELLIPTIC.TXT Designs both low pass and band pass elliptic filters (has zeros in the stop band).  The band pass design has a redundant coil, but every node has a capacitor to ground.
ELLIPBP.TXT Similar to ELLIPTIC.TXT but the band pass design is the normal transformation which has a floating node.
REVTCBP.TXT Reverse engineers a top coupled band pass design to find the low pass prototype.
BPBACK.TXT Reverse engineers an all pole band pass filter to find the low pass prototype.
BUTTER.TXT Designs Butterworth low pass or high pass RC active filters with a 3 pole section in odd ordered filters.
BNDPSS.TXT Designs RC active band pass filters with several topographies.  Does Butterworth, Tchebychev and Papoulis from internal calculations.  Other all pole designs can be input.